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1.
J Am Acad Dermatol ; 89(2): 235-242, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37094653

RESUMO

BACKGROUND: Gusacitinib is an oral inhibitor of Janus and Spleen tyrosine kinases. METHODS: The efficacy and safety of gusacitinib were evaluated in a double-blind, placebo-controlled, multicenter, phase 2 study in 97 chronic hand eczema patients randomized (1:1:1) to placebo or gusacitinib (40 or 80 mg) for 12 weeks (part A). Then, in part B (through week 32), the patients received gusacitinib. RESULTS: At week 16, patients receiving 80 mg gusacitinib showed a 69.5% (P <.005) decrease in the modified total lesion-symptom score versus 49.0% for 40 mg (P =.132), and 33.5% for placebo. Considerable improvement in Physician's Global Assessment was seen in 31.3% of patients receiving 80 mg versus 6.3% of placebo (P <.05). A 73.3% decrease in the hand eczema severity index versus placebo (21.7%) occurred in patients receiving 80 mg (P <.001). Patients receiving 80 mg experienced a considerable decrease in hand pain (P <.05). As early as week 2, considerable reductions over placebo in modified total lesion-symptom score (P <.005), Physician's Global Assessment (P =.04), and hand eczema severity index (P <.01) were observed (80 mg gusacitinib). Adverse events included upper respiratory infection, headache, nausea, and nasopharyngitis. CONCLUSIONS: Gusacitinib showed rapid improvement in chronic hand eczema patients and was well tolerated, warranting further investigations.


Assuntos
Eczema , Inibidores de Janus Quinases , Humanos , Quinase Syk/uso terapêutico , Resultado do Tratamento , Eczema/tratamento farmacológico , Eczema/induzido quimicamente , Método Duplo-Cego , Índice de Gravidade de Doença
2.
J Allergy Clin Immunol ; 144(4): 1011-1024, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31356921

RESUMO

BACKGROUND: Moderate-to-severe atopic dermatitis (AD) has been associated with significant disease burden and systemic abnormalities and often requires systemic treatments. Currently, safe and effective oral systemic treatments for moderate-to-severe AD are not yet available. ASN002 is an oral inhibitor of the Janus kinase/spleen tyrosine kinase signaling pathways, targeting several cytokine axes (TH2/TH22/TH17/TH1) and epidermal differentiation. OBJECTIVE: We sought to evaluate the effect of ASN002 on the cellular and molecular biomarker profile of patients with moderate-to-severe AD and to correlate changes in biomarkers to improvements in clinical severity measures and pruritus. METHODS: Thirty-six patients with moderate-to-severe AD were randomized to groups with dose escalation of ASN002 (20, 40, and 80 mg) and a placebo group. Skin biopsy specimens were performed at baseline, day 15, and day 29. Gene expression studies were conducted by using microarray and quantitative RT-PCR, and cellular infiltrates and protein expression were studied by using immunohistochemistry. RESULTS: ASN002 reversed the lesional skin transcriptome toward a nonlesional phenotype. It also rapidly and significantly suppressed key inflammatory pathways implicated in AD pathogenesis, including TH2 (IL4 receptor [IL4R], IL13, CCL13/monocyte chemoattractant protein 4, CCL17/thymus and activation-regulated chemokine, CCL18/pulmonary and activation-regulated chemokine, CCL22/macrophage-derived chemokine, and CCL26/eotaxin-3), TH17/TH22 (lipocalins, PI3/elafin, CCL20, S100A7/S100A8/S100A9, and IL36G/IL36RN), and TH1 (IFNG, CXCL9/CXCL11, and MX1) axes and barrier-related measures (filaggrin [FLG] and CLDN23). Significant improvements in AD gene signatures were observed predominantly in the 40- and 80-mg groups. Smaller and largely nonsignificant molecular changes were seen in the 20-mg and placebo groups. CONCLUSION: The Janus kinase/spleen tyrosine kinase inhibitor ASN002 significantly suppressed key AD inflammatory pathways, corresponding to clinical response. ASN002 might be an effective novel therapeutic agent for moderate-to-severe AD.


Assuntos
Acetonitrilas/uso terapêutico , Anti-Inflamatórios/uso terapêutico , Dermatite Atópica/tratamento farmacológico , Janus Quinases/antagonistas & inibidores , Piperidinas/uso terapêutico , Piridazinas/uso terapêutico , Quinase Syk/antagonistas & inibidores , Adulto , Biomarcadores/metabolismo , Dermatite Atópica/patologia , Método Duplo-Cego , Inibidores Enzimáticos/uso terapêutico , Epiderme/efeitos dos fármacos , Epiderme/patologia , Feminino , Proteínas Filagrinas , Humanos , Inflamação/tratamento farmacológico , Inflamação/patologia , Masculino , Pessoa de Meia-Idade
3.
Blood ; 113(17): 3938-46, 2009 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-19029442

RESUMO

Internal tandem duplication mutations of FLT3 (FLT3/ITD mutations) are common in acute myeloid leukemia (AML) and confer a poor prognosis. This would suggest that FLT3 is an ideal therapeutic target, but FLT3 targeted therapy has produced only modest benefits in clinical trials. Due to technical obstacles, the assessment of target inhibition in patients treated with FLT3 inhibitors has been limited and generally only qualitative. KW-2449 is a novel multitargeted kinase inhibitor that induces cytotoxicity in Molm14 cells (which harbor an FLT3/ITD mutation). The cytotoxic effect occurs primarily at concentrations sufficient to inhibit FLT3 autophosphorylation to less than 20% of its baseline. We report here correlative data from a phase 1 trial of KW-2449, a trial in which typical transient reductions in the peripheral blast counts were observed. Using quantitative measurement of FLT3 inhibition over time in these patients, we confirmed that FLT3 was inhibited, but only transiently to less than 20% of baseline. Our results suggest that the failure to fully inhibit FLT3 in sustained fashion may be an underlying reason for the minimal success of FLT3 inhibitors to date, and stress the importance of confirming in vivo target inhibition when taking a targeted agent into the clinical setting.


Assuntos
Antineoplásicos/farmacocinética , Antineoplásicos/uso terapêutico , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Antineoplásicos/efeitos adversos , Antineoplásicos/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Humanos , Leucemia/tratamento farmacológico , Leucemia/enzimologia , Leucemia/genética , Mutação/genética , Ligação Proteica , Tirosina Quinase 3 Semelhante a fms/genética , Tirosina Quinase 3 Semelhante a fms/metabolismo
4.
Mol Cancer Ther ; 20(8): 1327-1337, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34045226

RESUMO

The 5T4 oncofetal antigen (trophoblast glycoprotein) is expressed in a wide range of malignant tumors but shows very limited expression in normal adult tissues. ASN004 is a 5T4-targeted antibody-drug conjugate (ADC) that incorporates a novel single-chain Fv-Fc antibody and Dolaflexin drug-linker technology, with an Auristatin F hydroxypropylamide payload drug-to-antibody ratio of approximately 10-12. The pharmacology, toxicology, and pharmacokinetic properties of ASN004 and its components were investigated in vitro and in vivo ASN004 showed high affinity for the 5T4 antigen and was selectively bound to and internalized into 5T4-expressing tumor cells, and potent cytotoxicity was demonstrated for a diverse panel of solid tumor cell lines. ASN004 induced complete and durable tumor regression in multiple tumor xenograft models, derived from human lung, breast, cervical, and gastric tumor cell lines having a wide range of 5T4 expression levels. A single dose of ASN004, as low as 1 mg/kg i.v., achieved complete tumor regression leading to tumor-free survivors in the A431 cervical cancer model. In head-to-head studies, superior activity of ASN004 was demonstrated against trastuzumab-DM1, in a low-5T4/high-HER2 expressing gastric tumor model, and 10-fold greater potency was found for ASN004 against the 5T4-targeted ADC PF-06263507 in a lung tumor model. In marmoset monkeys, ASN004 was well tolerated at doses up to 1.5 mg/kg Q3W i.v., and showed dose-dependent exposure, linear pharmacokinetics, and markedly low exposure of free payload drug. Taken together, these findings identify ASN004 as a promising new ADC therapeutic for clinical evaluation in a broad range of solid tumor types.


Assuntos
Anticorpos Monoclonais Humanizados/química , Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Imunoconjugados/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Glicoproteínas de Membrana/antagonistas & inibidores , Anticorpos de Cadeia Única/química , Animais , Apoptose , Neoplasias da Mama/imunologia , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proliferação de Células , Feminino , Humanos , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Nus , Camundongos SCID , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
5.
Clin Pharmacokinet ; 46(4): 281-90, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17375980

RESUMO

Escitalopram is the (S)-enantiomer of the racemic selective serotonin reuptake inhibitor antidepressant citalopram. Clinical studies have shown that escitalopram is effective and well tolerated in the treatment of depression and anxiety disorders. Following oral administration, escitalopram is rapidly absorbed and reaches maximum plasma concentrations in approximately 3-4 hours after either single- or multiple-dose administration. The absorption of escitalopram is not affected by food. The elimination half-life of escitalopram is about 27-33 hours and is consistent with once-daily administration. Steady-state concentrations are achieved within 7-10 days of administration. Escitalopram has low protein binding (56%) and is not likely to cause interactions with highly protein-bound drugs. It is widely distributed throughout tissues, with an apparent volume of distribution during the terminal phase after oral administration (V(z)/F) of about 1100L. Unmetabolised escitalopram is the major compound in plasma. S-demethylcitalopram (S-DCT), the principal metabolite, is present at approximately one-third the level of escitalopram; however, S-DCT is a weak inhibitor of serotonin reuptake and does not contribute appreciably to the therapeutic activity of escitalopram. The didemethyl metabolite of escitalopram (S-DDCT) is typically present at or below quantifiable concentrations. Escitalopram and S-DCT exhibit linear and dose-proportional pharmacokinetics following single or multiple doses in the 10-30 mg/day dose range. Adolescents, elderly individuals and patients with hepatic impairment do not have clinically relevant differences in pharmacokinetics compared with healthy young adults, implying that adjustment of the dosage is not necessary in these patient groups. Escitalopram is metabolised by the cytochrome P450 (CYP) isoenzymes CYP2C19, CYP2D6 and CYP3A4. However, ritonavir, a potent inhibitor of CYP3A4, does not affect the pharmacokinetics of escitalopram. Coadministration of escitalopram 20mg following steady-state administration of cimetidine or omeprazole led to a 72% and 51% increase, respectively, in escitalopram exposure compared with administration alone. These changes were not considered clinically relevant. In vitro studies have shown that escitalopram has negligible inhibitory effects on CYP isoenzymes and P-glycoprotein, suggesting that escitalopram is unlikely to cause clinically significant drug-drug interactions. The favourable pharmacokinetic profile of escitalopram suggests clinical utility in a broad range of patients.


Assuntos
Transtornos de Ansiedade/tratamento farmacológico , Citalopram/farmacocinética , Depressão/tratamento farmacológico , Inibidores Seletivos de Recaptação de Serotonina/farmacocinética , Adolescente , Adulto , Fatores Etários , Idoso , Criança , Citalopram/administração & dosagem , Interações Medicamentosas , Humanos , Hepatopatias , Insuficiência Renal , Inibidores Seletivos de Recaptação de Serotonina/administração & dosagem , Fatores Sexuais
6.
Pharmacogn Mag ; 13(Suppl 3): S567-S572, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29142416

RESUMO

BACKGROUND: Aluminum chloride (AlCl3) is a known potent environmental neurotoxin causing progressive neurodegenerative changes in the brain. The herb Pluchea lanceolata is commonly known as "Rasana" and used as a nerve tonic in neuroinflammatory conditions in Indian system of medicine. OBJECTIVE: To evaluate the neuroprotective activity of hydroalcoholic extract of P. lanceolata in chronic AlCl3-induced neurotoxicity in Swiss albino mice. MATERIALS AND METHODS: Albino mice were categorized into four different groups; Group 1served as vehicle control, Group 2 mice were administered with AlCl3, 40 mg/kg body weight by intraperitoneal route for 45 consecutive days. Groups 3 and 4 mice were administered with AlCl3, 40 mg/kg body weight intraperitoneal for 45 consecutive days along with hydroalcoholic extract of P. lanceolata at 200 and 400 mg/kg body weight. RESULTS: Chronic administration of AlCl3 resulted in behavioral deficits, triggered lipid peroxidation, increased acetylcholinesterase (AChE) activity, and histological alterations. Co-administration of hydroalcoholic extract of P. lanceolata attenuated many of the AlCl3-induced alterations such as behavioral, lipid peroxidation, AChE, and histological changes of brain tissue. CONCLUSION: The results of the present study have demonstrated the protective role of hydroalcoholic extract of P. lanceolata against AlCl3-induced neurotoxicity in Swiss albino mice. The neuroprotective efficacy of P. lanceolata can help reduce the symptoms caused by toxic protein aggregates in several degenerative diseases. SUMMARY: The hydro alcoholic extract of Pluchea lanceolata showed neuroprotective activity in albino mice against AlCl3 toxicityThe benefits of Pluchea lanceolata against AlCl3 toxicity includes reduced lipid peroxidation and acetylcholine esterase activity with improved behavioral functionsThe hydro alcoholic extract of Pluchea lanceolata rendered protection against AlCl3 in forebrain, midbrain, cerebellum and hippocampusTherefore Pluchea lanceolata holds pharmacological potentials for treating diseases associated with neuronal toxicity. Abbreviations used: HAPL: Hydro alcoholic extract of Pluchea lanceolata; CAT: Catalase; GSH-Px: Glutathione peroxidase; SOD: Superoxide dismutase; TBARS: Thio-barbituric acid reactive substances; MDA: Malondialdehyde; AChE: Acetylcholine esterase; AOT: Acute oral toxicity; CNS: Central nervous system; H2O2: Hydrogen peroxide; ML: molecular layer; GL: granular layer; MC: microcytic changes; BV: blood vessels; DG: dentate gyrus; PC: pyramidal cells; LD: Lethal dose; ANOVA: Analysis of variance; SEM: Standard error of mean; PCL: Pyramidal cell layer; OCL: Outer granular layer; BV: blood vessels; PM: Pia mater.

7.
Clin Pharmacol Ther ; 79(1): 134-43, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16413248

RESUMO

OBJECTIVE: Our objective was to evaluate the pharmacokinetics of the Alzheimer's disease treatment memantine in subjects with normal and impaired renal function. METHODS: This was a single-center, single-dose, open-label study. Thirty-two subjects aged 18 to 80 years were assigned to 1 of 4 groups (8 subjects each) based on baseline creatinine clearance: normal renal function (>80 mL/min), mild renal impairment (50-80 mL/min), moderate renal impairment (30-49 mL/min), and severe renal impairment (5-29 mL/min). A single 20-mg memantine dose was administered under fasting conditions. Assessments included pharmacokinetic and safety measures. RESULTS: Thirty-one subjects completed the study. There were no relevant differences in maximum memantine plasma concentration between subjects with normal and impaired renal function of any severity. The mean area under the plasma concentration versus time curve extrapolated to infinity was similar between subjects with normal and mildly impaired renal function but increased by 60% (95% confidence interval [CI], 24%-97%) and 115% (95% CI, 77%-152%) in subjects with moderate and severe renal impairment, respectively. Simulations predicted steady-state maximum concentration values of 82 ng/mL (95% CI, 70-95 ng/mL), 85 ng/mL (95% CI, 70-101 ng/mL), and 128 ng/mL (95% CI, 109-147 ng/mL) in healthy subjects, those with mild renal impairment, and those with moderate renal impairment, respectively, for the recommended dosing regimen of 10 mg twice daily; for subjects with severe renal impairment, a steady-state maximum concentration value of 84 ng/mL (95% CI, 68-101 ng/mL) was predicted for a dosing regimen of 5 mg twice daily. CONCLUSION: On the basis of the predicted steady-state plasma concentrations with the use of the current dosing regimen of 10 mg twice daily, no dosage adjustments are needed for patients with mild or moderate renal impairment. A target dose of 5 mg twice daily is recommended in patients with severe renal impairment.


Assuntos
Dopaminérgicos/farmacocinética , Nefropatias/metabolismo , Memantina/farmacocinética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Cromatografia Líquida de Alta Pressão , Creatinina/sangue , Dopaminérgicos/administração & dosagem , Dopaminérgicos/efeitos adversos , Feminino , Meia-Vida , Humanos , Testes de Função Renal , Masculino , Memantina/administração & dosagem , Memantina/efeitos adversos , Pessoa de Meia-Idade
8.
Anc Sci Life ; 36(1): 48-55, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28182020

RESUMO

BACKGROUND: This paper explores the role that Ayurveda can play in the management of Iron Deficiency Anaemia, a major nutritional deficiency disorder affecting people across the globe. METHODOLOGY: Forty (40) patients suffering from Iron deficiency anaemia as per WHO guidelines, between the age group of 20 to 60 yrs of either sex participated in the study. Study was a randomized, controlled, open label clinical study. Patients were randomly divided into two groups: Group D (n = 20) received Dhari avaleha 10 g twice a day after food. Group K (n = 20) received capsules Kasisa bhasma 125 mg thrice a day. Both interventions were administered for 30 days and the subjects were followed up for next 30 days with placebo capsules to assess the sustainability of the effects. Assessments were done at baseline, 30th and 60th days. Primary outcome measure was hemoglobin estimation (Hb) and secondary outcome measures were the other hematological parameters such as Red blood cell (RBC) indices, total RBC count, Packed Cell volume (PCV) and Peripheral Blood smear study. RESULTS: Both interventions produced significant improvements (P < 0.001). Kasisa bhasma was better compared to dhatri avaleha in terms of primary (P < 0.0001) and secondary outcomes. Comparison of outcomes from base line - 30th day, base line - 60th day and 30th - 60th day showed significant (P < 0.0001) improvement in both the groups in parameters such as haemoglobin, MCV and MCH. Hence improvements sustained during placebo intervened sustainability period also. CONCLUSIONS: Study effectively shows that Kasisa bhasma is better then Dhatri avaleha. Improvements by both interventions were sustained even during the sustainability period.

9.
J Evid Based Complementary Altern Med ; 21(3): 194-201, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26207023

RESUMO

BACKGROUND: Panchakarma (biopurification methods) is one of the modes of ayurveda to treat disorders of the body. Virechana karma (therapeutic purgation), one among the Panchakarma, is a purification process that is commonly used to treat metabolic disorders like obesity and diabetes mellitus. Hence this study was planned to provide evidence through animal experiments. METHODS: Albino rats were subject to Virechana karma (therapeutic purgation) to evaluate the influence of therapy and its mechanism over fructose-induced metabolic syndrome. RESULTS: Results show that Virechana is effective in the management of the metabolic syndrome with decrease in the fecal fat content, fasting blood glucose, serum triglyceride, and reduced fatty changes in liver, heart, and kidney in comparison with the positive control group. CONCLUSION: Experimental evaluation showed decrease in fatty acid in the storage like liver, kidney, heart, and muscle adipose tissue can indirectly increase the insulin sensitivity in insulin receptor present at skeletal muscles.


Assuntos
Frutose/efeitos adversos , Ayurveda , Síndrome Metabólica/terapia , Animais , Glicemia/metabolismo , Feminino , Humanos , Resistência à Insulina , Masculino , Síndrome Metabólica/induzido quimicamente , Síndrome Metabólica/metabolismo , Ratos , Ratos Wistar
10.
Clin Ther ; 27(10): 1596-606, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16330295

RESUMO

BACKGROUND: The high prevalence rates of both Alzheimer's disease (AD) and type 2 diabetes mellitus in the elderly population suggest that concomitant pharmacotherapy is likely. Given the renal tubular transport and extensive urinary excretion of memantine and metformin, it was of interest to assess the pharmacokinetic and pharmacodynamic interaction with glyburide/metformin. OBJECTIVE: The primary goal of this study was to determine whether an in vivo pharmacokinetic or pharmacodynamic interaction exists between memantine (an uncompetitive, moderate-affinity, N-methyl-D-aspartate receptor antagonist with fast blocking/unblocking kinetics that is available in the United States for moderate to severe AD) and glyburide/metformin (a combination pharmacotherapy formulation approved for glycemic control in patients with type 2 diabetes mellitus). METHODS: In this single-center, multiple-dose, open-label study, healthy adult subjects received a single oral dose of memantine hydrochloride (20 mg) on day 1. After a 14-day washout period, subjects were orally administered 1.25-mg glyburide/250-mg metformin BID with food for 6 days. On day 21, subjects were coadministered memantine (20 mg) and glyburide/metformin with food. Assessments included determination of pharmacokinetic parameters for memantine and the antidiabetic agents when administered alone and in combination, pharmacodynamic measurements of blood glucose levels, and analyses of tolerability. RESULTS: The study population consisted of 24 subjects (13 women, 11 men; 79.2% white) with a mean (SD) age of 26.1 (5.6) years and a mean (SD) weight of 69.5 (11.3) kg. Twenty-one subjects completed the study: 2 discontinued due to adverse events judged unrelated to study medication, and 1 withdrew consent. No significant pharmacokinetic or pharmacodynamic interactions were observed between memantine and glyburide/metformin. Adverse events included dizziness (41.7% of patients) with memantine administration and gastrointestinal effects (nausea, 9.1 %; vomiting, 9.1%; abdominal cramps, 13.6%) with glyburide/metformin administration. CONCLUSIONS: No pharmacokinetic interactions between memantine and glyburide/metformin were detected in this study of healthy young volunteers. Memantine had no effect on the pharmacodynamic activities of glyburide and metformin, and the drug combination was well tolerated in this population.


Assuntos
Glibureto/farmacologia , Glibureto/farmacocinética , Memantina/farmacologia , Memantina/farmacocinética , Metformina/farmacologia , Metformina/farmacocinética , Adulto , Doença de Alzheimer/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Combinação de Medicamentos , Interações Medicamentosas , Feminino , Glibureto/administração & dosagem , Humanos , Masculino , Metformina/administração & dosagem
11.
Ayu ; 35(2): 148-51, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25558159

RESUMO

BACKGROUND: Osteoarthritis (OA) is the most common joint disorder. In Ayurveda the disease Sandhigata Vata resembles with OA, which is described under Vatavyadhi. Treatment provides symptomatic relief, but the underlying pathology remains unchecked due to the absence of effective drugs. In the management of Sandhigata Vata, all the Acharyas have described the employment of Bahya Snehan, Swedana, Abhyantara Tikta Snehapana, Basti treatment and Guggulu Prayoga. AIM: To evaluate the effect of Ksheerbala Taila Anuvasana Basti in Sandhigata Vata. MATERIALS AND METHODS: In the present study, 30 patients of Sandhigata Vata were given Anuvasana Basti with Ksheerabala Taila. Subjective assessment of pain by visual analog scale and swelling, tenderness, crepitus and walking velocity were graded according to their severity. RESULTS: Significant results (P < 0.05) were found in all the cardinal symptoms - Pain (Sandhiruja), Swelling (Shotha), tenderness, crepitus and walking velocity. Radiological findings showed no significant changes. CONCLUSION: Anuvasana Basti with Ksheerabala Taila was significant in the subjective symptoms of Sandhigata Vata.

12.
J Clin Pharmacol ; 52(10): 1468-81, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22162533

RESUMO

This model-based analysis quantifies the population pharmacokinetic-pharmacodynamic efficacy and safety/tolerability relationships of orally administered istradefylline, a selective adenosine A(2A) receptor antagonist, in healthy participants and patients with Parkinson disease. Data from 6 phase 2/3 clinical trials comprised the population database, with 1760 and 1798 patients contributing to the efficacy and safety/tolerability analyses, respectively. The relationship between istradefylline area under the curve at steady state and percentage OFF time was described by a nonlinear model (Emax) based on time for the disease progression/placebo response component and an Emax model for the effect of istradefylline. The typical maximum decrease in percentage OFF time due to istradefylline exposure would be 5.79% (95% confidence interval = 4.09%-7.49%) with one-half of the maximum effect reached at an exposure of 1690 ng × hr/mL (95% confidence interval = 199-3180 ng × hr/mL). The pharmacokinetic-pharmacodynamic relationships for dyskinesia and dizziness were described by an Emax model, and for nausea, a power model was used. The probabilities of dyskinesia and dizziness are expected to plateau at a dose of 40 mg/d, and the probability of nausea is expected to continually rise as the dose is increased. Collectively, these results support a starting istradefylline dose of 20 to 40 mg/d.


Assuntos
Antagonistas do Receptor A2 de Adenosina/administração & dosagem , Doença de Parkinson/tratamento farmacológico , Purinas/administração & dosagem , Antagonistas do Receptor A2 de Adenosina/efeitos adversos , Antagonistas do Receptor A2 de Adenosina/farmacocinética , Tontura/induzido quimicamente , Relação Dose-Resposta a Droga , Discinesias/etiologia , Humanos , Modelos Biológicos , Náusea/induzido quimicamente , Doença de Parkinson/metabolismo , Doença de Parkinson/fisiopatologia , Purinas/efeitos adversos , Purinas/farmacocinética
13.
J Clin Pharmacol ; 51(1): 40-52, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20200269

RESUMO

This model-based analysis quantifies the population pharmacokinetics (PK) of orally administered istradefylline, a selective adenosine A(2A) receptor antagonist, in healthy subjects and patients with Parkinson's disease, including the estimation of covariate effects on istradefylline PK parameters. Istradefylline plasma concentration data from 8 phase 1 and 8 phase 2/3 studies conducted in 1449 patients and normal, healthy volunteers aged from 18 to 87 years were best described by a 2-compartment model with first-order absorption parameterized in terms of apparent oral clearance (CL/F), apparent central volume of distribution (V2/F), apparent intercompartmental clearance (Q/F), apparent peripheral volume of distribution (V3/F) and a first-order absorption rate-constant (Ka). The typical population PK parameters were CL/F (5.76 L/h), V2/F (198 L), Q (21.6 L/h), V3/F (307 L), and Ka (0.464 h(-1)) for a 70-kg, nonsmoking Caucasian who had 55.6 kg of lean body mass, no presence of CYP3A4 inhibitors, and unknown food status. Smoking and CYP3A4 inhibitors as concomitant medications were important predictors of istradefylline exposure. Istradefylline area under the concentration-time curve at steady-state increased 35% (95% confidence interval, 18%-55%) in the presence of CYP3A4 inhibitors and decreased 38% (95% confidence interval, 26%-50%) in smokers. The population PK model described the observed concentration data well and was deemed appropriate for further evaluation of the istradefylline exposure-response relationship in patients with Parkinson's disease.


Assuntos
Antagonistas do Receptor A2 de Adenosina/farmacocinética , Modelos Biológicos , Doença de Parkinson/tratamento farmacológico , Purinas/farmacocinética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Estudos de Casos e Controles , Ensaios Clínicos Fase I como Assunto , Ensaios Clínicos Fase II como Assunto , Ensaios Clínicos Fase III como Assunto , Citocromo P-450 CYP3A/metabolismo , Inibidores do Citocromo P-450 CYP3A , Bases de Dados Factuais , Interações Medicamentosas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fumar/efeitos adversos , Distribuição Tecidual , Adulto Jovem
15.
Ann Pharmacother ; 38(9): 1389-94, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15266045

RESUMO

BACKGROUND: Memantine, a low- to moderate-affinity, uncompetitive N-methyl-D-aspartate receptor antagonist, was approved in the US for treatment of moderate to severe Alzheimer's disease in October 2003. OBJECTIVE: To determine whether an in vivo pharmacokinetic interaction exists between memantine and the acetylcholinesterase (AChE) inhibitor donepezil. METHODS: In this open-label, multiple-dose study, 24 healthy subjects (aged 18-35 y) received oral administration of memantine 10 mg on day 1. Following a 14-day washout period, subjects were orally administered donepezil 5 mg once daily for 7 days on an outpatient basis. Beginning on day 22, the donepezil dosage was doubled for 22 days to the target dose of 10 mg once daily, with the last donepezil dose concomitantly administered with memantine 10 mg on day 43. Assessments included pharmacokinetic as well as safety parameters. In addition, AChE inhibition was measured in red blood cells by radiolabeled-enzyme assay following administration of donepezil alone and after a single memantine dose. RESULTS: Data from 19 subjects who completed the study indicated no significant pharmacokinetic interactions between a single dose of memantine and multiple doses of donepezil. Percent maximum inhibition of AChE activity (mean +/- SD) by donepezil was 77.8 +/- 7.3% and not significantly different upon coadministration of a single dose of memantine (81.1 +/- 5.7%). Two subjects withdrew due to adverse events while taking donepezil alone. Single memantine doses administered with multiple donepezil doses were well tolerated. CONCLUSIONS: The pharmacokinetic and pharmacodynamic data from this study indicated a lack of interaction between memantine and donepezil, suggesting that memantine and donepezil may be safely and effectively used in combination.


Assuntos
Inibidores da Colinesterase/farmacocinética , Antagonistas de Aminoácidos Excitatórios/farmacocinética , Indanos/farmacocinética , Memantina/farmacocinética , Piperidinas/farmacocinética , Acetilcolinesterase/metabolismo , Administração Oral , Adolescente , Adulto , Inibidores da Colinesterase/sangue , Inibidores da Colinesterase/farmacologia , Donepezila , Interações Medicamentosas , Antagonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Humanos , Indanos/sangue , Indanos/farmacologia , Masculino , Memantina/farmacologia , Piperidinas/sangue , Piperidinas/farmacologia
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